Image Forming Apparatus

1. An image forming apparatus, comprising: a microcomputer; and a central processing unit (CPU), disposed in a main control board, configured to control overall operations of the image forming apparatus and to change a voltage level of a reset signal input to the microcomputer so that the microcomputer stops according to the reset signal in a sleep mode.

2. The image forming apparatus according to claim 1 , further comprising a switch configured to be turned on or off to supply an operating voltage to an element, wherein the switch is turned off by a switching signal being output when the microcomputer is stopped.

3. The image forming apparatus according to claim 2 , wherein the element includes at least one of an indicator configured to indicate whether an apparatus is powered on or not, and a display configured to output a screen.

4. The image forming apparatus according to claim 1 , further comprising at least one of a first switch and a second switch, wherein the first switch is configured to be turned on or off to supply an operating voltage to an element, and the second switch is configured to be turned on or off to supply the operating voltage to the microcomputer, and wherein at least one of the first switch and the second switch are turned off by the reset signal being input to the microcomputer.

5. The image forming apparatus according to claim 4 , further comprising a third switch configured to be turned on or off according to the voltage level of a reset signal received from the CPU.

6. An image forming apparatus, comprising: a microcomputer; a central processing unit (CPU) configured to change a voltage level of a reset signal input to the microcomputer so that the microcomputer stops according to the reset signal in a sleep mode; and a switch configured to be turned on or off to supply an operating voltage to an element, wherein the switch is turned off by a switching signal being output when the microcomputer is stopped, wherein the element includes an indicator configured to indicate whether an apparatus is powered on or not, and the switch includes a pull-down resistor and a transistor connected to the pull-down resistor, the indicator and the operating voltage.

7. The image forming apparatus according to claim 6 , wherein the indicator includes a light-emitting diode (LED).

8. A power control circuit, comprising: a microcomputer; an indicator to visually indicate that power of an apparatus is at a power-on mode to distinguish between a sleep mode and a power-off mode; and a first switch to be connected to the indicator electrically and to be turned on and off by a switching signal of the microcomputer, wherein a power is supplied to the indicator when the first switch is turned on at the power-on mode, and wherein the power is not supplied to the indicator when the first switch is turned off at the power-off mode.

9. The power control circuit according to claim 8 , wherein the first switch is turned on when the microcomputer is not operated.

10. The power control circuit according to claim 9 , further comprising: a second switch configured to be turned on when the voltage level of a reset signal received from a CPU is high and to be turned off when the voltage level of the reset signal is low.

11. The power control circuit according to claim 10 , further comprising: an input unit to receive an input of various sets of information and to transmit information to the microcomputer.

12. The power control circuit according to claim 11 , further comprising: a display configured to display a screen; and wherein the power is supplied to the microcomputer, the input unit and the display when the second switch is turned on, and wherein the power is not supplied to the microcomputer, the input unit and the display when the second switch is turned off.

13. The power control circuit according to claim 11 , further comprising: a third switch configured to be turned on when the voltage level of a reset signal received from a CPU is high and to be turned off when the voltage level of the reset signal is low.

14. The power control circuit according to claim 13 , wherein a branching operating voltage branched from the power is supplied to the microcomputer and the input unit when the third switch is turned on, and the branching operating voltage branched from the power and being supplied to the microcomputer and the input unit is blocked when the third switch is turned off.

15. The power control circuit according to claim 11 , wherein the microcomputer determines an operation mode of an apparatus according to the information input through the input unit.